Rosalind Lutece is quoted at the very beginning of BioShock Infinite as saying "The mind of the subject will desperately struggle to create memories where none exist...". She is seen sitting in front of Booker in the boat where they are rowing him to the lighthouse.

The quote comes from Lutece's book Barriers to Trans-Dimensional Travel, written in 1889.

In December 2012, Ken Levine called Lutece one of his favorite characters during an "Ask Me Anything" session on Reddit. [n]

Spoiler Warning: Would you kindly avoid the section below unless you've already finished the game? Proceed only at your own risk.

Rosalind Lutece is usually seen with her apparent brother, Robert Lutece. The two are highly unusual and seem to possess knowledge that neither Booker DeWitt or Elizabeth do, and both seem to always know what the other is about to say, constantly finishing each other's sentences.

Rosalind is also one of the individuals responsible for giving the city of Columbia its wings. Her peers refer to it as quantum levitation. However, she despises this description, saying that levitation is a magician's trick. In reality, the atoms she is levitating simply fail to fall, remaining at a fixed height and keeping the city of Columbia in the air. Additionally, she is responsible for the technology that created the extradimensional tears encountered throughout Columbia. Comstock used them to make his prophecies, the Finks used them to steal technology and music, and Rosalind used them to meet her "brother."

It is revealed during the events of the storyline that the two are in fact not brother and sister, but are actually the same person. Rosalind is from the world where Zachary Comstock and Columbia exist, and Robert is from an alternate universe that Rosland "tore" into, where she found Robert, her alternate male version.

The interaction between the two is possible because they have harnessed technology that can open tears in the universe, and the two having meet due to being able manipulate an atom, changes to which become apparant in both universes. This allowed them to communicate in Morse code using dots and dashes, much like a telegraph.

In order to prevent the truth about Elizabeth's origin from coming out, Comstock attempts to murder them, shutting down their machines while they are in use. However, they are not killed, they are only unstuck in time. This accounts for their ability to seemingly appear and disappear at will.